617 | The Hidden Assumption in Every Retirement Calculator
SEP 14, 202660 MIN
Description
Most retirement calculators assume your money needs to last until age 95. But if you're 55 years old today, average life expectancy is actually 79 for men and 82 for women. This single hidden assumption could mean the difference between retiring five years earlier or leaving millions unspent.
Key Topics Discussed
00:00:00 - Introduction: The Hidden Assumption
Brad introduces the concept that retirement calculators make an invisible assumption about longevity—typically planning to age 90-95—and explains why this matters for financial independence planning.
00:05:30 - Why Planning to 95 Is the Default
Dr Bobby Dubois and Aubrey Williams explain why financial advisors default to age 95, the fear of running out of money, and how this ignores the risk of over-saving and under-living.
00:12:00 - Layers of Financial Conservatism
Brad discusses multiple layers of conservative assumptions in retirement planning: lower returns, lower withdrawal rates, zero Social Security, and now longevity assumptions.
00:15:45 - Real Life Expectancy Numbers
Dr Bobby provides actuarial data showing average life expectancy from birth (71-76) versus age 55 (79-82), and the probability of reaching age 90.
00:21:00 - The Financial Impact of Longevity
Aubrey presents modeling showing how nest egg requirements change dramatically based on longevity assumptions—from $714K at age 79 to 41% higher at age 90.
00:28:30 - Dynamic Planning and Annual Updates
Discussion of how mortality-adjusted planning changes over time and why annual plan updates are essential rather than lock-and-load strategies.
00:35:00 - Tools to Estimate Your Longevity
Dr Bobby outlines practical methods: actuarial calculators, family history, cardiovascular risk calculators like the AHA Prevent tool, and genetic testing including APOE for dementia risk.
00:45:00 - Biological Age vs Chronological Age
Discussion of biological clock testing and why these tests aren't ready for prime time, despite heavy marketing in the longevity space.
00:50:00 - Extending Your Healthspan
Dr Bobby covers evidence-based interventions to reduce risk of heart disease and dementia: exercise, sleep, blood pressure control, weight management, and avoiding smoking.
00:58:00 - Wrap-up and Resources
Final thoughts on updating assumptions, where to find Dr Bobby and Aubrey, and invitation for community feedback on future analysis scenarios.
Notable Quotes
Brad Barrett: "Every financial calculator has to make assumptions... but there's one assumption that's almost never discussed, even though it might be the single biggest one in the entire model. How long does your money need to last?"
Dr Bobby Dubois: "The nest egg you need depends a lot on how long you're going to live. Imagine you're sixty-five and you're only going to live five years. Well, you don't need a whole lot of money. Imagine you're sixty-five and you're going to live to be one hundred five."
Aubrey Williams: "Planning to ninety-five does answer one question, but by far, it's not the only question we should be looking at... it completely ignores the opposite risk that we live a shorter life and either we've saved too much, worked too long or spent too little."
Dr Bobby Dubois: "If you are 60, what's the likelihood you'll live to be 90? For men, it's about a third, meaning two thirds won't. Women, it's about half might live to be 90."
Aubrey Williams: "If hitting FI at 65, you live to age 79, you need $714,000. But if you live to 90, 11 years longer, then that nest egg needs to be 41% higher."
Key Takeaways
Calculate your own life expectancy using actuarial tools from the Society of Actuaries rather than accepting calculator defaults of 90-95
Research your family history of longevity—genetics account for roughly 50% of how long you'll live, especially for those reaching 100+
Use the American Heart Association's Prevent calculator to assess your 10-year and 30-year cardiovascular disease risk
Consider genetic testing for APOE status to understand dementia risk, available through 23andMe, Function Health, or the Alzheimer's Organization for $100-130
Commit to annual retirement plan updates that adjust for your current age, health status, and market conditions rather than locking into one number forever
Review the 'layers of conservatism' in your plan: expected returns, withdrawal rates, Social Security assumptions, and now longevity expectations
Prioritize the high-impact health interventions: 7-8 hours of sleep, regular strength training, blood pressure control, maintaining healthy weight, and not smoking
Start strength training now to build 'muscle IRA'—you lose 1-2% muscle mass yearly after age 30-35, so build capacity early before inevitable decline
Reassess exercise risk as you age—consider lower-impact alternatives that reduce injury risk which carries higher recovery costs in later decades
Resources and Links
OpenPath Financial (Aubrey Williams)
Dr Bobby Live Long and Well Website
AHA Prevent Calculator
ChooseFI Episode 566: Risk-Based Guardrails in Drawdown
Sleep Masterclass with Dr Bobby Dubois
Dr Bobby Evidence Newsletter
Society of Actuaries Mortality Tables
Live Long and Well with Dr. Bobby Podcast
Function Health Genetic Testing
Alzheimer's Organization APOE Testing
23andMe Genetic Testing
Lancet Commission on Dementia Prevention
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